Human immunodeficiency virus type-1 (HIV-1) causes acquired immunodeficiency syndrome (AIDS). AIDS is a serious and deadly disease, with over 33 million people infected worldwide. Everyday, about 7,000 people become infected with HIV, and about 6,000 people die of AIDS and AIDS-related illnesses. Since HIV, the pathogen that causes AIDS, was first isolated in the early 1980s, diverse research has been conducted regarding the treatment of AIDS around the world. However, researchers have not succeeded in developing an effective vaccine capable of preventing and treating AIDS.
There are two types of HIV: HIV-1 and HIV-2. Both types of HIV are transmitted by sexual contact, through blood, and from mother to child, and they appear to cause clinically indistinguishable AIDS. However, it seems that HIV-2 is less easily transmitted, and the period between initial infection and illness is longer in the case of HIV-2.
Worldwide, the predominant virus is HIV-1. The relatively uncommon HIV-2 type is concentrated in West Africa and is rarely found elsewhere. The strains of HIV-1 can be classified into four groups: the “major” group M, the “outlier” group O and two new groups, N and P. These four groups may represent four separate introductions of simian immunodeficiency virus into humans.
Group O appears to be restricted to west-central Africa and group N—a strain discovered in 1998 in Cameroon—is extremely rare. In 2009 a new strain closely relating to gorilla simian immunodeficiency virus was discovered in a Cameroonian woman. It was designated HIV-1 group P.1 More than 90% of HIV-1 infections belong to HIV-1 group M. Within group M there are known to be at least nine genetically distinct subtypes (or clades) of HIV-1. These are subtypes A, B, C, D, F, G, H, J and K.
Since the late 1990, various types of diagnostic kits to detect HIV have been developed. An immunological method using an antibody that recognizes a specific protein of HIV is one of the most widely used techniques for the diagnosis of HIV infection. These methods have reduced sensitivity when compared to nucleic acid testing assays. Methods for detecting HIV-1 have also been developed that use cultivated cells and nucleic acid probes. These methods require highly skilled professionals and are time consuming. In order to overcome these limitations, research into various diagnostic assays utilizing the polymerase chain reaction (PCR) has been conducted. In these methods, a specific portion of a nucleic acid sequence is amplified exponentially in a suitable reaction mixture containing at least DNA polymerase and template specific primers.
There remains an unmet need in the art to develop an accurate and reliable real-time method for detecting samples contaminated with HIV-1.